Antigranulocyte antibodies and deranged immune function associated with phenytoin-induced serum sickness.

A phenytoin-associated serum-sickness-like syndrome was followed by severe pancytopenia in a 17-year-old female. Serum obtained during the acute phase of her illness contained antibodies against homologous eosinophils and neutrophils, antibodies against autologous neutrophils, and antibodies to phenytoin. The serum also inhibited bone marrow granulocyte colon formation in vitro. Lymphocyte transformation by pokeweed mitogen was impaired and, after recovery, the patient's lymphocytes were transformed in vitro by the addition of phenytoin. These data demonstrate that profound derangements of immunity can be associated with a phenytoin-induced serum-sickness-like illness.